This is false. But I wouldn’t expect less from an elitist alliance player.
Illdari are not alliance or horde, they are there own thing.
However the Illdari is kind of like a brotherhood. There are members of the Illdari who joined the factions while simultaneously being apart of that faction.
Kind of like the Ebon blade.
Also. Kael’thas was still the leader of the blood elves until he turned on them.
Although it’s true that I abandoned the blood elves completely and joined illidan.
In legion we were sworn back into our respective factions.
Get educated.